Quantifying the Effects of Acquisition Parameters in Cardiac SPECT Imaging and Comparison with Visual Observers

Significant debate remains whether the established imaging protocols for myocardial perfusion SPECT delivers optimal image quality. This debate has been intensified with the introduction of advanced iterative reconstruction techniques which differ considerably from the FBP reconstruction technology commonly available when the current protocols were established. In order to characterize and classify image quality affecting factors, simulations combined with time consuming observer studies are often used. In this work we seek to simplify these image assessment tasks by performing numerical characterizations based on real data, and try to unite quantitative performance with visual impression derived from human observer studies. For this purpose, we assess the response of cardiac image quality to variations in acquisition and reconstruction protocol. We analyze anthropomorphic phantom data derived from large dimensioned acquisitions via subsampling in terms of counts and spatial and angular resolution. Data is reconstructed using FBP and OSEM-3D ("Flash3D") with parameter variations and the reconstructed volumes are quantitatively analyzed for cardiac relevant features like myocardial uniformity and resolution. Receiver Operating Characteristic (ROC) studies are performed for selected imaging parameters. Results obtained characterize the sensitivity of the cardiac image quality to some changes in the imaging protocol like angular step, orbit radius and collimation and show correlations of key quantitative measures and related ROC behavior.